Fluorescent pteridine-based nucleoside analogs that can be site- specifically incorporated into DNA oligonucleotides through a phosphodiester linkage have been developed and patented. The fluorescence properties of a series of these compounds have been characterized and potential applications are being investigated. These new fluorophores are promising probes for the study of protein/DNA interactions, because they are not attached to DNA externally and they do not appear to disrupt the tertiary structure of DNA. Rapid fluorescence-based assays for HIV-1 integrase and alkylguanine-DNA- akyltransferase have been developed, and the utility of these fluorophores as hybridization probes has been patented and is under investigation. A number of collaborative studies investigating the potential applications of these new research tools are also underway. - DNA repair, Fluorescent probes, Integrase, Nucleoside analogs, - Human Tissues, Fluids, Cells, etc.